Is talaq via speed post/email in 2010 valid & Mehar due w/ witnesses?

I am from New Delhi.Married in August 2000.Two children,daughter 6 years old and son 3 years old now.Our married life was not happy.I work in Private Company and wife works in Govt.job. Due to differences between me and my wife,on 12th July,2008,left home,took a flat on rent, called her parents from U.P. and started living seperately.All efforts for reconcilation failed.She had even filed complaint against me in Police Station,and filed maintenance petition in 2009 against me in court,matter of which is pending. After all reconcilation efforts,including even by Court appointed mediators failed,I sent her letter of First Talaq on 26th april 2010 written in my hand writing and duly signed by two witnessess through Speed Post at her Residence address in Delhi and sent scannned copy of letter also by email to her.On phone she acknowledged receipt of both these.Then I sent second letter of Talaq again on 29th May 2010 in my own hand writing and signed by same two witnesseses again by speed post and scaned copy by email.I had also mentioned in that the reference of first talaq and that it was the second one.I got Delivery Report of Speed Post.Then on 3rd July 2010,I sent the Final and third Talaq Letter to her in same manner in my hand writing and signed by same two witnesses.I also emailed scanned copy by email to her.In that letter too I had mentioned reference of earlier two talaqs and said it is the third and final one.Again I got receipt of acknowldegement and delivery report from her end.In that third letter I had also mentioned that I want to pay her Mehar amount of Rs.one lakh only by cheque /draft and I want her to meet me at a neutral place of conbvenience so that I can hand it to over to her. Kindly note that the court case is for providing maintenance for children only.It has nothing to do with talaq.This court case she had filed in May/June 2009 much before I sent her Talaq letter in April 2010.she had filed that maintenanace case under Section 125 saying that she had been thrown out of house and as she is living seperately she needs maintenanace from my end. NOW IN LIGHT OF ABOVE FACTS: I want to know whether this talaq is proper and valid or not? Still her mehar amount is due to be paid.I am willing to pay her the amount.I had mentioned that clearly to her in my final and third talaq letter.The Bank Draft of Rs.One lakh is ready in her name.But I want to pay her in presence of witneses only. I want to know that in between the period when the mehar is yet to be paid, is talaq complete or not?